JPH1078084A - Power transmitting belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To widely extend belt life by providing sufficient bending resistance under a low/high temperature environment and even when this temperature difference is increased. SOLUTION: This power transmitting belt comprises a bonding rubber layer 3 burying a core wire 2 along a belt lengthwise direction and a compressed rubber layer 4 layered on the bonding rubber layer 3. In the compressed rubber layer 4 of the power transmitting belt, a rubber composition of high saturation copolymer partially hydrogenating a ternary copolymer acrylonitrile-butadiene- carboxilic acid ester is used, in the bonding rubber layer 3, a rubber composition of nitrile hydride adding hydrogen by 80% or more double bond in a molecule of copolymer is used, a difference between an iodine number of nitrile hydride thus used and an iodine number of the high saturation copolymer used in the compressed rubber layer 4 is less than 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission belt, and more particularly to a power transmission belt including a V-belt and a V-ribbed belt which have improved heat resistance, cold resistance and bending resistance to greatly extend the life of the belt. About.

[0002]

2. Description of the Related Art In recent years, V-belts and V-belts used in automobiles
Power transmission belts such as ribbed belts have been required to have a high degree of heat resistance as engine output and fuel efficiency are required. For example, a V-ribbed belt including an adhesive rubber layer and a compressed rubber layer having at least two rib portions extending in the belt length direction rotates a pulley mounted on a crankshaft of an automobile by simultaneously rotating a plurality of accessories such as alternates. For this purpose, these pulleys are wound in a serpentine shape. Therefore, V
The ribbed belt is required to have high heat resistance and bending resistance, and hydrogenated nitrile rubber (HNBR) obtained by hydrogenating chloroprene, chlorosulfonated polyethylene (CSM) or acrylonitrile-butadiene copolymer.
Rubber compounds using heat-resistant elastomers such as the above have come to be used. In particular, hydrogenated nitrile rubber is extremely excellent in ozone resistance and heat resistance as compared with conventional NBR, but cold resistance may be inferior to chloroprene rubber depending on the content of nitrile group and the degree of unsaturation. .

In recent years, the operating environment temperature of power transmission belts has been further widened from a low temperature to a high temperature, and a nitrile group-containing highly saturated copolymer rubber composition having improved cold resistance has been developed. Was. Regarding this, for example, Japanese Patent Publication No. Hei 7-88440, Japanese Patent Publication No. Hei 3-10944
8 and Japanese Patent Publication No. 3-109449.

[0004]

However, V-belts and V-belts
For the adhesive rubber layer of power transmission belts such as ribbed belts,
When a nitrile group-containing highly saturated copolymer rubber composition whose cold resistance is improved is used, the amount of acrylonitrile in the copolymer is reduced, so that the oil resistance is reduced and during the belt running. When oil is applied, there is a risk that peeling from the compressed rubber layer or peeling from the cord will occur due to swelling of the adhesive rubber layer.

Further, an alkylated chlorosulfonated polyethylene rubber composition is used for a compressed rubber layer, and a hydrogenated nitrile rubber composition or a chloroprene rubber composition is used for an adhesive rubber layer. Is disclosed in Japanese Patent Application Laid-Open No. Hei 4- 211748. However, this belt also requires further improvement in an environment where a temperature difference is required from a low temperature to a high temperature.

The present invention has been made to solve such a problem, and has sufficient bending resistance under a low-temperature environment or a high-temperature environment, and even when the temperature difference is large, and increases the life of the belt. It is an object of the present invention to provide a power transmission belt that is greatly extended.

[0007]

That is, the invention of claim 1 of the present application comprises an adhesive rubber layer in which a core wire is embedded along the belt length direction, and a compressed rubber layer laminated on the adhesive rubber layer. In a power transmission belt, a rubber composition of a highly saturated copolymer obtained by partially hydrogenating a terpolymer of acrylonitrile-butadiene-carboxylate is used for the compression rubber layer, and the copolymer is used for the adhesive rubber layer. Using a rubber composition of a hydrogenated nitrile in which the double bond in the molecule is hydrogenated by 80% or more, the iodine value of the hydrogenated nitrile used for the adhesive rubber layer and the highly saturated copolymer used for the compressed rubber layer By making the difference in iodine value of less than 13 and making the values close to each other, the adhesion at the interface between the adhesive rubber layer and the compressed rubber layer can be maintained at a high level, and peeling during belt running can be prevented. it can.

[0008] Further, acrylonitrile-
Since a highly saturated copolymer rubber composition obtained by partially hydrogenating a butadiene-carboxylate terpolymer is used, the belt life is improved by improving not only cold resistance but also heat resistance and bending resistance. It can be greatly extended, and furthermore, because the rubber composition of hydrogenated nitrile is used for the adhesive rubber layer, even if oil is applied during running of the belt, the occurrence of separation from the compressed rubber layer due to swelling of the adhesive rubber layer is suppressed. be able to.

[0009] The invention of claim 2 of the present application relates to a rubber composition used for the compressed rubber layer, wherein 100 parts by weight of a highly saturated copolymer obtained by partially hydrogenating a terpolymer of acrylonitrile-butadiene-carboxylate is used. 1 to 30 parts by weight of staple fibers to improve the durability of the belt by increasing the lateral pressure resistance, and by lowering the friction coefficient of the side surface of the belt, it is possible to reduce Abnormal noise can be prevented.

According to the third aspect of the present invention, since the short fibers are particularly aramid fibers, the friction coefficient on the side surface of the belt is reduced, and the abnormal noise during the running of the belt in the initial stage of driving can be further prevented. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A power transmission belt shown in FIG.
This belt 1 is a belt 1 in which a cord 2 composed of a high-strength, low-elongation cord made of polyester fiber, aromatic polyamide fiber, or glass fiber is spirally embedded in an adhesive rubber layer 3. A compression rubber layer 4 which is an elastic layer is provided on the lower side. The compressed rubber layer 4 is provided with a plurality of ribs 7 having a substantially triangular cross section extending in the longitudinal direction of the belt, and one to several plies of attached canvas 5 with rubber attached to the surface of the belt.

The power transmission belt shown in FIG.
And an adhesive rubber layer 3 in which the core wire 2 is embedded in a spiral shape.
And a compression rubber layer 4 which is an elastic body layer below the compression rubber layer 4. Further, each surface of the compression rubber layer 4 and the adhesive rubber layer 3 has
Several plies of rubberized canvas 5 are laminated. Needless to say, the V-belt 9 may be a belt with a gok in which the compressed rubber layer 4 is provided with grooves at regular intervals along the longitudinal direction.

The highly saturated copolymer obtained by partially hydrogenating a terpolymer of acrylonitrile-butadiene-carboxylate as a raw rubber used for the compressed rubber layer 4 is obtained by emulsifying acrylonitrile, butadiene and unsaturated carboxylate. A rubber obtained by hydrogenating butadiene in a copolymer rubber obtained by a polymerization method by an ordinary method, and has excellent cold resistance and heat resistance. Acrylonitrile bound to the highly saturated copolymer is 15 to 30% by weight, and the iodine value is 10%.
４０40 g / 100 g.

The unsaturated carboxylic acid esters used herein include acrylates and methacrylates having an alkyl group having about 1 to 18 carbon atoms, such as methyl acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate and ethyl methacrylate, and monoethyl maleate. And mono- and dialkyl esters of unsaturated carboxylic acids such as dimethyl itaconate and di-n-butyl itaconate. As the compounding agent, sulfur, a sulfur-donating compound for tetramethylthiuram disulfide, a sulfur vulcanization system comprising various vulcanization accelerators, and an organic peroxide vulcanization system such as dicumyl peroxide are used. In addition, reinforcing agents such as carbon black, silica, talc and calcium carbonate, plasticizers, process oils, antioxidants and the like are used.

On the other hand, the hydrogenated nitrile rubber as a raw rubber used for the adhesive rubber layer 3 is a rubber obtained by hydrogenating an acrylonitrile-butadiene copolymer, and has a hydrogenation ratio of 80% or more, and has a heat resistance and In order to exhibit the ozone resistance, it is preferably 90% or more. Hydrogenation rate 8
When the hydrogenated nitrile rubber is less than 0%, the heat resistance and the ozone resistance are extremely reduced. Considering oil resistance and cold resistance,
The amount of bound acrylonitrile is preferably in the range of 20-45%. Further, the iodine value is 10 to 40 g / 100 g.

In the present invention, a highly saturated copolymer obtained by partially hydrogenating an acrylonitrile-butadiene-carboxylate terpolymer used for the compressed rubber layer 4 and the adhesive rubber layer 3 and a hydrogenated nitrile rubber are used. 13 difference in iodine value
It is necessary to bring the values close to each other, preferably to less than 10, preferably less than 10. Thereby, the adhesive force at the interface between the compressed rubber layer 4 and the adhesive rubber layer 3 can be maintained at a high level. However, if the difference in iodine value is larger than 13, the adhesive strength in a high-temperature atmosphere will be insufficient.

Short fibers made of nylon 6, nylon 66, polyester, cotton, and aramid are mixed into the compressed rubber layer 4 to improve the lateral pressure resistance of the compressed rubber layer 4 and to be in contact with the pulley. The short fibers protrude from the surface of the compressed rubber layer 4 to reduce the friction coefficient of the compressed rubber layer 4 and reduce noise during belt running. Among these short fibers, aramid short fibers having rigidity and strength and abrasion resistance are most effective.

In order for the above-mentioned aramid short fibers to sufficiently exhibit the above-mentioned effects, the fiber length of the aramid fibers should be 1-20.
mm, the addition amount is 1 to 30 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. The aramid fiber is an aramid having an aromatic ring in its molecular structure, such as, for example, Conex, Nonex, Kevlar, Technora, Twaron, and the like. When the amount of the aramid short fiber is less than 1 part by weight, the rubber of the compressed rubber layer 4 has a disadvantage that the rubber easily sticks and wears. On the other hand, when the amount exceeds 30 parts by weight, the short fiber is contained in the rubber. It will not be evenly dispersed.

Further, in order to improve the adhesion of the short fibers to the hydrogenated nitrile rubber, the short fibers are bonded by a treatment liquid selected from an epoxy compound and an isocyanate compound. Examples of the epoxy compound include polyhydric alcohols such as ethylene glycol, glycerin and pentaerythritol, reaction products of polyalkylene glycols such as polyethylene glycol with halogen-containing epoxy compounds such as epichlorohydrin, resorcinol, bis (4- (Hydroxyphenyl) dimethylmethane, phenol. Formaldehyde resin, resorcinol.
Reaction products with polyhydric phenols such as formaldehyde resins and halogen-containing epoxy compounds. This epoxy compound is used by being mixed with an organic solvent such as toluene and methyl ethyl ketone.

Examples of the isocyanate compound include 4,4'-diphenylmethane diisocyanate, toluene 2,4-diisocyanate, P-phenyl diisocyanate, and polyaryl polyisocyanate. This isocyanate compound is also used by being mixed with an organic solvent such as toluene and methyl ethyl ketone.

[0021]

The present invention will be described in more detail with reference to the following examples. Example 1, Comparative Examples 1 to 3 In the V-ribbed belt manufactured in this example, a core wire made of a polyester fiber rope was embedded in an adhesive rubber layer,
On the upper side, a single layer of cotton canvas with rubber is laminated, while on the other side of the adhesive rubber layer is a compressed rubber layer having three ribs in the longitudinal direction of the belt. The obtained V-ribbed belt is a K-type 3-ribbed belt having a length of 1100 mm according to the RMA standard, a rib pitch of 3.56 mm, and a rib height of 2.9 m.
m, belt thickness 5.3 mm, and rib angle 40 °.

Here, the compressed rubber layer and the adhesive rubber layer were each prepared from the rubber composition shown in Table 1, kneaded with a Banbury mixer, and then rolled with a calender roll. The compressed rubber layer contains short fibers and is oriented in the belt width direction. The short fibers were previously immersed in 90 g of toluene in a processing solution containing 90 g of PAPI (a polyisocyanate compound manufactured by Kasei Upjohn Co., Ltd.).

[0023]

[Table 1]

Next, the heat resistance of the V-ribbed belt 1 was evaluated. The running test used for this evaluation was performed by using a driving pulley 10 (120 mm in diameter) and a driven pulley 1 as shown in FIG.
1 (120 mm in diameter)
(Diameter 85 mm) and tension pulley 13 (diameter 45 m)
m), and was run at an atmospheric temperature of 120 ° C. The number of rotations of the driving pulley is 4
At 900 rpm, the load on the driven pulley was 12 PS, and an initial tension of 558.6 N was applied to the tension pulley. Also,
The idler pulley 12 engages on the back of the V-ribbed belt 1, and its wrap angle is about 120 degrees. By this running test method, the time until cracks occurred in the rib portions of the belt was measured. Table 2 shows the results.

Further, the bending resistance of the V-ribbed belt was evaluated. The running test used for this evaluation was a combination of a driving pulley (120 mm in diameter), a driven pulley (120 mm in diameter), and an idler pulley (50 mm in diameter). A belt is hung on each pulley of this testing machine, a load of 100 kgf is applied to the driven pulley, the idler pulley is engaged with the back surface of the V-ribbed belt 1, the winding angle is set to about 120 degrees, and the idle The time required for cracking due to bending while running under a load was measured, and the bending performance was compared. Table 2 shows the results.

Further, the low-temperature durability of the V-ribbed belt 1 was evaluated. This evaluation method uses a drive pulley (diameter 45m).
m) and a belt on a driven pulley (45 mm in diameter)
A load of 30 kgf was applied to the driven pulley, left for 24 hours in an atmosphere of -35 ° C, and allowed to run for 5 minutes.
After stopping for one minute, the time until the belt cracked was measured. Table 2 shows the results.

[0027]

[Table 2]

As described above, the V-ribbed belt of the present embodiment is particularly suitable for a combination of a highly saturated copolymer obtained by partially hydrogenating an acrylonitrile-butadiene-carboxylate terpolymer and a hydrogenated nitrile rubber. Because the iodine value of the same was equalized, the adhesive force at the interface between the adhesive rubber layer and the compressed rubber layer was maintained at a high level even at high temperature and low temperature traveling compared to the comparative example, and peeling during belt traveling was prevented,
It turns out that it is excellent in heat resistance, bending resistance, and cold resistance.

[0029]

As described above, the invention of claim 1 of the present application is
The difference between the iodine value of the hydrogenated nitrile used for the adhesive rubber layer and the iodine value of the highly saturated copolymer obtained by partially hydrogenating the terpolymer of acrylonitrile-butadiene-carboxylate used for the compressed rubber layer is less than 13. By bringing the values close to each other, the adhesive force at the interface between the adhesive rubber layer and the compressed rubber layer can be maintained at a high level, and the peeling during belt running can be prevented. −
Since a rubber composition of a highly saturated copolymer obtained by partially hydrogenating a terpolymer of butadiene-carboxylate is used, not only cold resistance but also heat resistance are improved and flex resistance is improved. This has the effect of greatly extending the belt life.

According to a second aspect of the present invention, in addition to the effect of the first aspect, the rubber composition used for the compressed rubber layer is obtained by partially hydrogenating an acrylonitrile-butadiene-carboxylic acid ester terpolymer. 1 to 30 parts by weight of staple fiber with respect to 100 parts by weight of the highly saturated copolymer to improve the side pressure resistance to improve the durability of the belt and to reduce the friction coefficient of the side surface of the belt. Thus, there is an effect that abnormal noise during running of the belt at the initial stage of driving can be prevented.

According to the invention of claim 3 of the present application, since the short fibers are particularly aramid fibers, the friction coefficient of the side surface of the belt is reduced, and the abnormal noise during the running of the belt in the initial stage of driving can be further prevented. effective.

[Brief description of the drawings]

FIG. 1 is a sectional view of a V-ribbed belt according to the present invention.

FIG. 2 is a sectional view of a V-belt according to the present invention.

FIG. 3 is a side view of a V-ribbed belt heat resistant running test machine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 V-ribbed belt 2 core wire 3 adhesive rubber layer 4 compressed rubber layer 7 rib

Claims (3)

[Claims] 1. A power transmission belt comprising an adhesive rubber layer in which a cord is buried along the belt length direction and a compression rubber layer laminated on the adhesive rubber layer, wherein acrylonitrile-butadiene- A highly saturated copolymer rubber composition obtained by partially hydrogenating a carboxylic acid ester terpolymer was used, and at least 80% of the double bonds in the copolymer molecules were hydrogenated to the adhesive rubber layer. A power characterized in that the difference between the iodine value of the hydrogenated nitrile used for the adhesive rubber layer and the iodine value of the highly saturated copolymer used for the compressed rubber layer is less than 13 using a hydrogenated nitrile rubber composition. Transmission belt. 2. The rubber composition used in the compressed rubber layer is characterized in that staple fibers of 1 to 100 parts by weight of a highly saturated copolymer obtained by partially hydrogenating a terpolymer of acrylonitrile-butadiene-carboxylate are used. The power transmission belt according to claim 1, which contains 30 parts by weight. 3. The power transmission belt according to claim 2, wherein the short fibers are aramid fibers.